This invention relates to a system which optimizes the flow of a lubricant over portions of a scroll compressor which become hot during reverse rotation or loss of charge, and then passing the heated lubricant onto a motor protector.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor a first scroll member has a base and a generally spiral wrap extending from the base. The wrap of the first scroll member interfits with the wrap from a second scroll member. The second scroll member is caused to orbit relative to the first, and refrigerant is entrapped between the scroll wraps. As the second scroll member orbits the size of the compression chambers which entrap the refrigerant are reduced, and the refrigerant is compressed.
There are certain design challenges with a scroll compressor. As an example, while the scroll compressor efficiently compresses refrigerant when rotated in a proper forward direction, there are undesirable side effects if the scroll compressor is driven to rotate in a reverse direction. Moreover, if the level of refrigerant or charge level, being passed through the compressor is lower than expected, there may also be undesirable side effects. Among the many undesirable side effects is an increased heat level at the scroll compressor members.
One safety feature incorporated into most sealed compressors is the use of a motor protector associated with the electric motor for driving the compressor. The same is true in a scroll compressor, wherein a motor protector is typically associated with the stator for the electric motor. The motor protector operates to stop rotation of the motor in the event there is an electrical anomaly, or if the motor protector senses an unusually high temperature. However, the problems mentioned above with regard to reverse rotation and loss of charge typically cause heat to increase at the compressor pump set, or the scrolls, which is relatively far from the motor. Thus, it may take an undue length of time for the additional heat being generated in the compressor pump set to pass to the motor protector.
In the disclosed embodiment of this invention, lubricant is caused to flow over a portion of the compressor pump set and be heated, at least when there are adverse conditions in the compressor pump set. This heated lubricant is then passed to a motor protector. This will cause the motor protector to trip the motor and stop further rotation.
In preferred embodiments, the heated portion of the compressor over which the lubricant is passed is the non-orbiting scroll. Alternatively, in some embodiments the heated lubricant can pass over the orbiting scroll.
In one general type of disclosed embodiment, the flow of lubricant back to the motor protector is selective, and will only occur if a particularly high temperature is reached. At other times, the lubricant is directed to a normal return path.
These and other features of the present invention can be best understood from the following specification and drawings, the following which is a brief description.